Which function can both a firewall and a router perform in a network?

A firewall and a router can both implement security defense functions, which is a crucial aspect of network management. Firewalls are primarily used to control incoming and outgoing network traffic based on predetermined security rules. They help to protect the network from unauthorized access and threats by inspecting packets and enforcing security policies.

Routers, while primarily responsible for directing data packets between different networks, also incorporate basic security features. Many modern routers come equipped with firewall capabilities, allowing them to filter traffic and provide a degree of protection against intrusions. This dual functionality enhances the overall security posture of a network.

The other choices represent functions that may not be natively or equally performed by both devices. For instance, prioritizing internet traffic involves Quality of Service (QoS) configurations, which some routers can handle, but firewalls typically focus more on security. Encrypting data during transmission is generally handled by dedicated encryption protocols and software rather than by firewalls or routers themselves. Managing user authentication is often the role of access control systems or specialized network devices rather than a core function of either firewalls or routers.